Method of installing a terminal to a plate



METHOD OF INSTALLING A TERMINAL TO A PLATE Filed Nov. '10, 1966 F I G. 4

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8 @150 James ,Ianrorno INVENTOR.

JOHN P. CHANDLER HIS ATTORNEY.

United States Patent 3,460,234 METHOD OF INSTALLING A TERMINAL TO A PLATE James Iantorno, Mamaroneck, N.Y., assignor to Sealectro gorporation, Mamaroneck, N.Y., a corporation of New ork Filed Nov. 10, 1966, Ser. No. 593,495 Int. Cl. B23p 11/00; H01r 9/00 US. Cl. 29-4321 1 Claim ABSTRACT OF THE DISCLOSURE This invention relates to self-fastening electrical terminals and relates more particularly to a novel terminal and method of mounting it, the terminal being designed primarily for mounting in a sheet metal housing or chassis wherein the terminal itself forms a male punch for the purpose of punching a hole in the sheet metal chassis or other mounting surface. A special tool forming a complemental female die cooperates with the punch element to flange the material surrounding the hole downwardly and at the same time mounts the terminal securely and permanently within the hole. This terminal can be of either the stand-off or feed-through variety. This annular flange is slightly undersize with relation to the main body of the terminal and the flange exerts a constrictive action on said body.

An important object of the invention is toprovide an insulated terminal and method of mounting it on a housing which greatly reduces the cost of installation, in that fabricating the hole or other preparation of the chassis is eliminated completely.

Self-fastening terminals presently known are generally designed so that two operations required to complete assembly of the unit: (a) the insulator passing through a special die penetrates the material and locks itself into position, and (b) the terminal is then forcibly inserted into the insulator which necessitates that the latter to be firmly secured during the process. Self-fastening hardware, such as nuts and studs, require either forced chassis material flow provided by the tooling, or the material flow caused by the nut or stud itself. Neither the selffastening terminal nor the nut mounting methods are desirable for stably fastening an insulated terminal to a thin metal chassis.

It is an object of the present invention to provide a low cost, self-fastening, insulated terminal which can be securely mounted in a suitable housing surface, said terminal consisting of two factory assembled parts, namely, the lead-through or stand-off electrical conductor pin and an insulator body or bushing in which the pin is firmly mounted. This bushing also serves as a male punch. The insulating bushing is preferably made from polymers which can be subjected to limited deformation but have an elastic tendency to return to their original shape, such as PPO and PTFE. The configuration of the insulator include a full diameter body section and a section of reduced diameter at the chassis entry end which becomes the male die or punch.

The method of the present invention includes the use of a novel combination tool which is designed to provide 3,460,234 Patented Aug. 12, 1969 a female die in the center for piercing in conjunction with the male punch and is spring loaded, being surrounded by a die which does not move during the second or flanging operation. In the first step, a hole is formed and a slug is punched out, and in the second step, which follows instantaneously the metal is drawn downwardly to form the flange.

In the drawing:

FIG. 1 is a side elevation of the improved terminal of the present invention;

FIG. 2 is a central vertical section taken through the novel combination punching and flanging tool;

FIG. 3 shows the position of the parts as the hole is punched;

FIG. 4 shows the second step where the flange is formed;

FIG. 5 shows the finished assembly;

FIG. 6 is a top plan view of the tool; and

FIG. 7 shows a modification in the shape of the secondary die, the shape being non-circular while the secondary die of FIG. 2 is round.

The terminal unit shown in FIG. 1 includes an electrical terminal or pin 10 shown here as being of the stand-off type, which is mounted in force fit relation in an insulating bushing made from one of the materials earlier mentioned and it includes an insulating body or bushing 11 having an enlarged flange 12 adjacent its upper end, engaged by a flange 13 on the pin 10, and a lower terminal section 14 of reduced diameter which forms the punch. A tapered portion 16 is formed between the two sections for a purpose to be described.

The special tool earlier mentioned is a two-part die including a primary femal die 18 which is mounted for sliding movement in a secondary or flanging die 19, both of tubular construction, the inner die having an external shoulder 20 which abuts against an inner annular shoulder 21 formed in the bore in the secondary die, the shoulder limiting upward movement of the primary =die which is urged in that direction by a spring 22.

To insert the insulated terminal in an unperforated sheet metal chassis or housing 24 the tool is placed in proper mounting location abutting the lower surface of the chassis and the bushing forcibly strikes the upper surface in a position in axial alignment with the tool, forming a hole 26 and punching out a slug 28. The tool is firmly supported during impact by the bushing and continued downward movement of the bushing causes the tapered section 16 to engage the annular margin of the hole and progressively draws the metal downwardly to form flange 29 while at the same time driving die 18 downwardly as shown in FIG. 4. The flange is in large measure formed by the tapered section 16 and the full diameter section of the body 11 finishes the work. Continuing the ram movement permits the full mounting diameter of the bushing to draw or flange the material into the secondary or stationary die 19 while depressing the spring loaded center section 18. The full mounting diameter, being larger than the inside diameter of the flanged hole, provides an interference fit while its depth extends below the depth of the flange allowing the sharp metal edge to bite into the outer face of the bushing as it is driven downwardly. In other words, the interference fit, which is important is achieved because the wall thickness of the chassis is slightly greater than the clearance between bushing 11 and the inner annular surface of flanging die 19 as shown.

The tool is withdrawn downwardly and the mounting of the unit is complete as shown in FIG. 5. No tool or chuck for mounting the assembled terminal is shown since it can be any holding device used in press-type equipment. One of the points of novelty in the present process consists in using the plastic male die section 14 for punching the hole. The material out of which the bushing is made is not as hard as the metal normally used in dies and the edge may even fracture a bit during the operation but this does not render it ineffective to punch a hole in the thin chassis which is probably the only hole it will punch during its existence. The entire punching operation is done by this circular edge when mounting the stand-off terminal assembly of FIG. 1 and the pin should not extend below this edge during punching. A long pin is used for the feed-through type and it is pushed below this edge after finished mounting of FIG. 5 is completed.

FIG. 7 shows a modification in the tool wherein to provide for additional resistance to rotation, the shape of the secondary die can be made hexagonal as shown at 30. It may also be octagonal, or any conveniently tooled form tion, in a sheet metal plate, which consists in supporting that would assist in increasing the force required to rotate 1 the unit.

Resistance to pull-out can also be increased by tapering the secondary die several degrees, i.e. larger at entry end and smaller lower in the cavity to expose the sharp edge of the flange to the insulator.

While there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that many modifications and changes may be made therein without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claim, and that all modifications that come within the meaning and range of equivalency of the claim are intended to be included therein.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The method of mounting an electrical terminal assembly comprising an insulated bushing having a major diameter section and having a lower end of reduced diameter and a terminal pin mounted therein in force fit relathe lower face of the plate by inner and outer relatively moveable concentric hollow dies; punching a portion of the metal from the plate to form a hole in the plate while so supported by striking the plate in the area overlying the inner die bore with said lower end of the bushing which is substantially a complementary diameter to that of said inner die bore to leave plate material between the edge of the hole and the inner diameter of the outer concentric die; and continuing downward movement of said bushing to cause the major diameter section of said bushing to form a flange by drawing the said plate material downwardly against the inner bore of the outer die while the inner die is moved downwardly and the outer die supports the plate and supports the downwardly displaced metal to form a throat which receives the bushing in force fit relation.

References Cited UNITED STATES PATENTS 2,126,161 8/1938 Woodward. 2,432,949 12/ 1947 Thorngren. 3,204,328 9/1965 Klasek. 3,300,850 1/ 1967 Stearnagel 29432.1 1,831,556 11/1931 Figge 29432 2,433,312 12/1947 Weber 72327 2,887,157 5/1959 Rehdorf 72-327 2,898,671 8/1959 Helm. 3,111,750 11/1963 Moore et al. 3,195,227 7/1965 Prestige 29-630 X 3,261,909 7/1966 Rust et al 174-153 3,357,081 12/1967 Prestige 29432 X FOREIGN PATENTS 880,839 10/ 1961 Great Britaain.

JOHN F. CAMPBELL, Primary Examiner R. W. CHURCH, Assistant Examiner US. Cl. X.R. 

